Antibacterials Flashcards
3 classes of cell wall inhibitors + 5 subcategories
b-lactams
- Penicillins
- Aminopenicillins
- Cephalosporins
- Monobactams
- Carbapenems
Glycopeptides (Vancomycin)
Daptomycin
Cell wall inhibitor MOA
Bind to PBP —> no D-Alanine removal
= inhibit synthesis peptidoglycan wall
Mechanism of resistance to b-lactams
B-lactamases
Difference between benzathine, procaine, and sodium G penicillin
Benzathine: IM, more effect duration 1/mo.
Procaine: less pain, more effect duration 1/day
Sodium: fast and short
Probenecid function
Increase duration of penicillin by decreasing excretion
3 penicillinase-resistant drugs
Naficillin
Oxacillin
Dicloxacillin***
Dicloxacillin main indication
Staphylococcus skin and soft tissue infection
Rare (IV): endocarditis, osteomyelitis
Main side effect of penicillins
HYPERSENSITIVITY
Others: AI hemolytic anemia, interstitial nephritis
Indications for penicillin
Strep or staph
- Strep throat
- Rheumatic fever
- Viridans endocarditis
- B strep neonatal prophylaxis
- Actinomyces
- C.perfringens
- Pasteurella
- T.pallidum syphillis
Which penicillin is IV, which is oral?
Oral: V
IV: G
ONLY gram negative covered by penicillin
Neisseria meningitiditis —> meningitis
Cell wall inhibitors are bactericidial or bacteriostatic?
Bactericidial
Which MOOS are already mostly resistant against penicillins?
S.aureus
S.epidermiditis
4 aminopenicillin drugs
Ampicillin
Amoxicillin
Piperacillin
Ticarcillin
Main drugs for MRSA (3)
Vancomycin
Daptomycin
Linezolid
B-lactamase for each aminopenicillin
Amoxi + clav
Ampi + sulbac
Piper + tazobac
Ticar + clav
Which has broader spectrum: penicillins or aminopenicillins?
Aminopenicillins, they include some more gram -
Amoxicillin administration and indications (4)
ORAL
Strep throat
RTI: s.p, h.i, m.c
H.pylori
Borrelia lyme’s
Ampicillin administration and indications (3)
IV
Anaerobic: enterococcus**can be resistant
Listeria meningitis
E.coli GI and UTI
______ should be used as prophylaxis for s.p and h.i in a patient with asplenia. Also before dental procedures if endocarditis risk.
Amoxicillin
In what case to give piper-tazo or ticar-clav instead of other aminopenicillins?
PSEUDOMONAS
Hospital-acquired pneumonia or sepsis - serious
Aminopenicillin side effects aside from hypersensitivity
Liver injury amoxi
Steven-Johnson’s sx
Rash if EBV infection
B-lactam with broadest spectrum
Carbapenems
Carbapenem medications (hint: iMED)
Imipenem
Meropenem
Etrapenem
Doripenem
Which carbapenem is given with CILASTATIN to inhibit its degradation in renal tubules?
Imipenem
When others fail, we get the job done!
Talks about…
Carbapenems
Carbapenem administration and indications
IV
Anaerobic intra-abdominal
Pseudomonas
Meningitis
Which resists broad-spectrum b-lactamases: monobactams or carbapenems?
Carbapenems
Dangerous carbapenem side effect
Lowers seizure threshold
Monobactam medication name
Aztreonam
Aztreonam administration and indications
IV or IM
Gram - aerobic rods
IF ALLERGIC TO PENICILLIN
Pseudomonas
Meningitis, pneumonia or sepsis
UTIs
What type of drug is vancomycin?
Glucopeptide
Vancomycin MOA
Binds to D-alanine and transpeptidase can’t cut it
B-lactamases are inefficient
Vancomycin administration and indications
IV
Empiric for endocarditis1st
MRSA*1st
Meningitis with ceftriaxone
S.epidermiditis
Which bacteria is resistant to vancomycin?
Enterococcus
Turns D-ALA to D-LAC
ONLY oral administration of vancomycin is for:
C.difficile
4 vancomycin side effects
Red man sx: histamine
Thrombophlebitis
Oto/nephrotoxic
DRESS sx: eosinophilia
It’s important to monitor plasma levels of:
Vancomycin
Daptomycin MOA
Insert lipid tail to depolarize cell wall
Daptomycin is used for (2):
Vancomycin-resistant enterococcus
MRSA*****1st
Which antibiotic can’t be given in pneumonia because its inactivated by surfactant?
Daptomycin
Daptomycin main side effect
Myopathy
Monitor creatinine phosphokinase (CPK)
1st gen cephalosporins
Cephalexin
Cefazolin
Cephalothine
(Tip: all “ph” instead of “f”)
1st gen cephalosporin indications (4)
Gram + (strep or staph)
- strep throat
- cellulitis and abscess
- PEK UTIs: proteus, e.coli, klebsiella
- surgical prophylaxis
Which generation of cephalosporin is used for surgical preparation?
1st gen
Which cephalosporin is used for MRSA
5th gen - ceftaroline
Which cephalosporin is used for pseudomonas?
3rd: ceftazidime
4th: cefepime
2nd gen cephalosporins
Cefuroxime
Cefoxitin
Cefotetan
2nd gen cephalosporin uses
RARE
HENS gram - : H.i, Neisseria, Serratia
3rd gen cephalosporins
Ceftriaxone
Cefotaxime
Ceftazidime
3rd gen cephalosporin uses
Meningitis H.i - triax, taxi
Pseudomonas - tazi
Viridans
GI gram -
Sepsis empiric
Gonorrhea IM
Lyme’s
What is ceftriaxone given in combination with to treat Listeria?
Ampicillin
Cephalosporins don’t work versus:
Enterococcus
4th gen cephalosporin and uses
Cefepime
Pseudomonas
Meningitis
5th gen cephalosporin and uses
Ceftaroline
MRSA
Which drug does teicoplanin share mechanism with?
Vancomycin
Polymyxin B, what is it and uses
Concentration-dependent bactericidial
Cation polypeptides bind gram -
Pseudomonas, E.coli, Klebsiella, Acinetobacter, Enterobacter
Other name for polymyxin E
Colistin
Polymyxin B vs E
B: parenteral, ophthalmic, otic, topical
E: prodrug, IV or nebulizer
2 classes of protein synthesis inhibitors + 6 subclasses
30S:
- Tetracyclines
- Aminoglycosides
50S:
- Macrolides
- Lincosamides (Clindamycin)
- Cloramphenicol
- Oxazolidone (Linezolid)
30S inhibitors and their mechanism
Tetracycline: no tRNA access to A site
Aminoglycosides: irreversible binding —> misread
50S inhibitors and mechanism
Macrolides: inhibit A —> P translocation
Lincosamides (clindamycin): inhibit A —> P translocation
Chloramphenicol: bind to P site
Oxazolidone (linezolid): inhibit 70S formation
Which antibiotic causes RNA misread and what is the result?
Aminoglycosides
Bactericidial
Tetracyclin MOA and therefore resistance
Passive diffusion —> bacteria —> bind 30S
—> prevent aminoacyl tRNA binding to A site
Efflux pumps, mutations in ribosome
Antibiotic used mostly for infections acquired in the OUTDOORS
Tetracyclines
Tetracycline administration and indications
Oral or IV
Broad, even MRSA
Rickettsia*****1st line and other tick diseases
Endocarditis sheep —> doxicycline
Chlamydia pelvic and CAP
Atypical pneumonia
Brucellosis, Coxiella, Yersinia
Tetracycline main side effect
Tooth discoloration (deposits there)
Therefore, avoid in <8y/o and pregnant women
Also: photosensitivity
Antibiotic class that has notable fecal excretion
Tetracyclines
Which antibiotic classes have decreased absorption by cations and milk? (2)
Tetracyclines
Fluoroquinolones
Macrolide MOA and medication names
50S inhibit translocation from A site to P site
Azithromycin
Ezithromycin
Clarythromycin
Macrolide administration and indications
Oral or IV
H.pylori*****1st line clarythromycin
Chlamydia - azithro, erythro for neonates
LRI: pneumonia, MAC prophylaxis, atypical
Diphtheriae - e
Bordetella + family prophylaxis
Others: babeosis, bartonella
Macrolide main side effects (4)
GI
Jaundice - HEPATOTOXIC!!
Prolonged QT
Inhibit P450
Macrolides (inhibit/activate) P450.
Inhibit
Tigecyclin
Glycylcycline, binds to 30S like tetracycline but 3rd gen
Skin, soft tissue, intra-abdominal
Active even vs MRSA
Chloramphenicol indications
Meningitis in developing countries (cheapest)
Rocky mountain spotted fever —> rickettsia
—> In pregnancy, when doxicycline is not an option
Chloramphenicol side effects
Anemia - reversible or aplastic
Gray baby sx (flacid, hypothermia, shock)
Clindamycin indications
G(+) Anaerobic lung abscesses ***aspiration pneumonia
Bacterioides
MRSA cellulitis
C.perfringens
Acne
Endometriris - chlam or gono if doxi/cephalo don’t work
Gardenella vaginosis
Characteristic side effect of clindamycin
Diarrhea
C.difficile pseudomembranous colitis
Linezolid indications
Gram +
MRSA** 1st line
(Complicated skin/soft tissue)
Serious HAP
Vancomycin-resistant enterococcus
Linezolid main side effects (4)
Cytopenia
Optic neuropathy
Peripheral neuropathy
Serotonin sx
ONLY protein synthesis inhibitor that is bactericidial
Aminoglycosides
Aminoglycosides MOA
30S irreversible binding —> misread —> death
Can need cell wall inhibitor at the same time
Which cell wall inhibitors are given with aminoglycosides?
B-lactams
Or vancomycin
Aminoglycosides indications
Gram - aerobic bacilli
Which medication is given before colorrectal surgery?
Neomycin (Aminoglycosides)
Which antibiotic can be given vs intraluminal parasites?
Paromomycin (Aminoglycosides)
Which aminoglycoside is given for tick Franciscella and Yersinia?
Streptomycin
Which a minoglycoside is given for enterobacter, Serratia, or Klebsiella?
Gentamicin
Gentamicin uses
- UTIs
- Septicemia
- Nosocomial RTI
- Intra-abdominal
- Osteomyelitis
Which aminoglycosides can be used versus pseudomonas? (3)
Genta
Tobra
Amikacin
Why is amikacin more expensive than other aminoglycosides?
Broad spectrum
Resistant versus enzymes that break others down
Aminoglycosides main side effects (2)
OTOTOXICITY
- Vestibular and cochlear
- Teratogenic deafness
- Irreversible
NEPHROTOXICITY
- Acute tubular necrosis
- Increase creatinine (monitor)
Other: neuromuscular block
Linezolid MOA
Binds to 23S of 50S —> inhibit 70S formation
SMX and TMP MOAs
SMX: PABA analogue that inhibits dihydropteroate synthase
TMP: inhibits DHF reductase
TMP-SMX indications
UTI1st line
Acute prostatitis
Nocardia1st line
P.jirovecci pneumonia + prophylaxis in AIDS
Note: PYR-SFD for toxoplasmosis prophylaxis in AIDS
TMP-SMX has many side effects, the most significant being (3):
Hypersensitivity
Teratogenic
Pancytopenia
Displace drugs from albumin
Inhibit P450
Hemolytic anemia
TMP-SMX (inhibits/activates) P450.
Inhibits
What antibiotic is most commonly given for burns?
Silver sulfadiazine
Other: mafenide
Fluoroquinolones MOA
Inhibit topoisomerase
II: cipro
IV: moxi
Levo both
Which fluoroquinolone is used for gram + and what is its MOA?
Moxifloxacin
Inhibits topoisomerase IV
Which fluoroquinolone is used for gram - and what is its MOA?
Ciprofloxacine
Inhibit topoisomerase II
Fluoroquinolones are empiric treatment for _____
Pyelonephritis
Ciprofloxacine/levo indications
UTI: E.coli, proteus
GI: Shigella, salmonella, campylobacter
Complicated UTI: pseudomonas
Acute prostatitis
Osteomyelitis if px has sickle cell
Moxifloxacin/levo indications
Bacillus anthracis pneumonia
CAP
Atypical pneumonia
Fluoroquinolone main side effect + 2 extras
Tendon and cartilage damage
- don’t give to <10y/o or pregnant
Prolonged QT —> torsades
GI
Antimycobacterial dosing
4 for 2 mo. - RIPE
Followed by
2 for 4 mo. - RI
Which antimycobacterial can be used on its own for latent TB?
Isoniazid
Isoniazid MOA
Activated by KatG (mutations decrease KatG)
Inhibit mycolic acid synthesis
Why do 4 antimycobacterials have to be given together?
To avoid resistance
Isoniazid main side effects INH
Injury Nerves and Hepatocytes
- CNS: seizures
- PNS: neuropathy, paresthesias due to B6 defficiency
- Metabolic acidosis
- Inhibit P450
- Lupus
All antimycobacterials have this side effect
HEPATOTOXIC
Which vitamin should be given with isoniazid?
B6 / pyroxidine to avoid peripheral neuropathy
Which is the most potent antimycobacterial?
Rifampin
Rifampin MOA
Inhibit RNA polymerase (rpoB)
if it mutates = resistance
Which of these induces and which inhibits P450? Isoniacid/rifampin
Induce: rifampin
Inhibit: isoniacid
Rifampin can ONLY be given on its own in this disease
Meningitis PROPHYLAXIS
Characteristic rifampin side effect
Orange coloration of fluids - not damaging
Rifabutin is an alternative to ______ in the case of _____
Rifampin ; HIV
Ethambutol MOA
Inhibits arabinosyl transferase in WALL
—> inhibit carbohydrate formation
Ethambutol side effect
Optic neuritis
- Less visual acuity
- Red-green color blindness
Pyrazinamide side effect
Hyperuricemia, needle shaped uric acid crystals
Gout exacerbations
MAC treatment
Macrolide + ethambutol +- rifabutin
Also for prophylaxis when CD4<50
M.leprae treatment
DAPSONE + rifampin
Clofazime if lepromatous (lion-face)
Dapsone side effects
Agranulocytosis
Hemolytic anemia
Rifamycins are excreted via:
Feces
First line treatment for N.meningiditis
Ceftriaxone
First line treatment for Bartonella “whooping cough”
Macrolides
First line treatment for P.jirovecci
Sulfonamides
Safe with renal impairment DANCER
Doxycycline
Ampicillin
Naficillin
Ceftriaxone
Erythromycin
Rifampin
Nephrotoxic
tu SUgar TE VA A BEsar (gracias lu)
SUlfonamides
TEtracyclines
VAncomycin
Aminoglycosides
BEta-lactams
Contraindicated in pregnancy MCAT
Metronidazole
Chloramphenicol
Aminoglycoside
Tetracycline
Macrolides :)
ERika, CLAra, AZucena
Ototoxic
Aminoglycosides
Cardiotoxic
Macrolides
Drug-induced hemolytic anemia
3-5 cephalosporins
Sulfonamides
NOT IN CHILDREN
Tetracyclines
Fluoroquinolones
2nd line TB treatment (2 main)
Amikacin
Streptomycin